Automatic reverse brake



July 16, 1935. c. A. MATsoN AUTOMATIC REVERSE BRAKE Filed Nov. 25, 1952 5 Sheets-Sheet l July 16, 1935-' c. A. MATsoN 5 f 2,008,140

AUTOMATIC REVERSE BRAKE Filed Nov. 25, 1952 3 SheGtS-Sheet 2 July 16, 1935. c. A. MA'rsQN AUTOMATIC REVERSE BRAKE y vFiled Nov. 25, 1932 5 sheets-sheet 5 Patented July 16, 1935 UNITED STATES AUTOMATIC BRAKE Carl A. Matson, Lynniield, Mass., assigner to The Matson Company, Concord, N. H., a corporation of New Hampshire Application November 25, 1932, Serial No. 644,169

9 Claims.

My present invention relates to a brake mechanism, and Imore particularly to a novel and imn proved automatic reverse brake for automobiles or other mechanical devices.

I have heretofore devised several distinct mechanisms for accomplishing the highly desirable purpose of preventing inadvertent reverse movement of a motor vehicle, particularly on inclines, and the device of this application pertains to this same class or type oi mechanisms.

Another object of the present invention resides in the fact that my present device is highly efiicient in operation, being positive in use, rugged, durable and long lived, while yet possessing the advantages of simplicity and economy.

Another feature of the present invention resides in the fact that a machine equipped with my device may be moved in a rearward direction, either under its own power or by hand, by placing the normally operative brake mechanism in an inoperative condition or position, this being accomplished by simply moving the gear shift lever to reverse position and thence to neutral posin tion.

Another and important feature of the present invention resides in the fact that the locking elements, preferably rollers, are held out of idling engagement during the forward movement of the device.

The importance of this latter-mentioned feature will be instantly apparent to and understood by those skilled in this art, as the elimination of idling of the locking elements during movement of the device in a forward direction results in the total elimination of the major portion of the friction and Wear which would otherwise be imposed upon these locking elements or devices.

I accomplish this last mentioned and valuable feature by the provision of a novel member which I have herein termed a drag ring, associated with the locking elements which in this instance are illustrated as rollers, and which drag ring is so constructed and arranged as to move said rollers, on movement of the vehicle in a forward direction, to the large end of the wedge chambers,

thus removing them from contact with the fixed part of the device and preventing their idling during said forward movement, thus eliminating chattering, friction and wear, and greatly increasing the eiiiciency, positiveness and life of my novel device.

A further feature of the present invention resides in the provision of a novel member which I` have herein termed a ratchet ring, and its associated parts, as the fixed part of my novel reverse `brake mechanism. This ratchet ring is normally restrained from rotation by means of a novel pawl and latch mechanism which wilLof course, be hereinafter more fully described.

As a further novel feature of my invention, I mount this ratchet ring upon a memberiixed to a rigid part of the casing or housing of my device, thus still further eliminating wear which would ordinarily occur, and also reducing likelihood of unwanted rotation being imparted t'o said ring.

Another object of my invention resides in the construction and arrangement of the locking roller carrying means.

Other objects and features of the invention reside in the particular construction and arrange; ment of the device and parts thereof, and all of the foregoing, together with otherobjects and features of the invention, will be hereinafter more fully pointed out, described and claimed. p

Referring to the drawings illustratinga preferred embodiment of the present invention,

Fig. l is a side elevation of an automobile transmission mechanism, partly in section, i1

lustrating my invention applied thereto;

Fig. 2 is a plan sectional view on the line 2 2 of Fig. 1;

Fig. 3 is a fragmentary vertical sectional View on the line 3-3 of Fig. l, with the device in the position assumed during forward speed;

Fig. 4 is a vertical sectional View on the line` 3-3 of Fig. 1, with the locking rollers in braking position;

Fig. 5 is a fragmentary vertical sectional view, on an enlarged scale, on the line 5 5 of Fig. 4;

Fig. 6 is a fragmentary vertical sectional view similar to a part of Fig. 3, but on an enlarged scale; and p Fig. 7 is a fragmentary Vertical sectional View on the line lle-'l of Fig. 4.

Referring new to the drawings, for a particular description of the invention, its construction, assembly and operation, it designates a transmission casing provided with the usual transmission gearing and having rotatably mounted therein and extending through the rear end thereof a transmission shaft Il.

trated generally at l2. Mounted on thetop of the transmission casing ifi is a cover i3, in which is pivotally mounted the gear shift lever I 3a for operating the slide rods I4 and I5 associated with.

the speed changegearing within the casing I Il. Because of the presence of the freewheeling unit l2, itis necessary to equip said' slide rods with l Associated with said transmission shaft isy a free wheeling unit illus-.

Ya part of the casing I1.

extensions, in a manner and for a purpose to be hereinafter described in detail. Attached to the rear of the transmission casing I5 is a casing l1 open at the rear end and provided with a cover I8 that is secured in position by bolts I9.

Secured to the splined end of the transmission shaft I I by a nut 2| is one member 22 of the usual knuckle joint, the other member 23 being connected to the propeller shaft 24. The hub 25 of the member 22 is smoothed off, to provide a Vseat 26 (see Fig. 5) for a drag ring 21, said ring 21 being under pressure of the plungers 28 forced thereagainst by the springs 29 in. the recesses in the member 3l, said member being Xed to Interposed between the drag ring 21 and the member 22 is an anti-friction bearing 32, so that the drag of the plungers 28 on the ring 21 will not be aifected by any frictional resistance which might otherwise occur on the opposite side of said drag ring.

i Surrounding the member 3i and having a substantially close nt thereon, although there is a running clearance therebetween, is a member which I have herein referred to, for simplicity and clarity, as a ratchet ring, because of the fact that this ring is provided, on its periphery, with a plurality of spaced notches 34. Symmetrically arranged about the periphery of the member are recesses 35, said recesses forming, with the bore 36 of the ring 33, substantially wedge-shaped or tapered chambers, in each of which is rotatably mounted a roller 31.

From an inspection of Fig. l, it will be noted that While the` ratchet ring 33 is mounted on the member 3|, said ring projects outwardly from said member and surrounds the member 22, but

is spaced slightly therefrom, as clearly illustrated in enlarged detail in Fig. 6, so that the rotation of the member 22 will have no wearing effect on the bore of the ring 33 or on the periphery of the said member 22.

As will be noted from an inspection of Fig. 5, Y

each roller 31 is provided with a short projecting stud 38, on one side, and with a longer projecting stud 39 on the opposite side. Unitedfto the member 22 by screws 40, and on each side thereof, are rings 4I and 42, the ring 4I having extensions 43 in each of which is an inclined, slightly arcuate slot 44, the ring 42 being provided with corresponding slots 44. rIhe drag ring 21 is provided with radial recesses or slots 45, corresponding in number to the rollers 31. The short studs 38 are located in the slots 44 in the ring 4i, and the long studs 39 project through the slots 44 in the ring 42 and into the radial slots or recesses 45 in the drag ring 21.

Pivoted at 46 is a lever 41 having thereon a pawl 48 and located above the pivot 45 is a second pivot 49 on which is mounted a lever 5Fl having a latch 5I and also being provided with a cam surface 52.

The slide rod I4 is provided with an extension 53 which has a short cam groove 54, and the slide rod I5 is provided with an extension 55 which has an elongated cam groove 56, in which rest the camsV 51 and 58 respectively on the arm 59, which in turn -is pivoted in the casingY I1 at 60.

The extension 55 is provided with a cam surface 6I and With a cut-away portion 62, as clearly shown in Fig. 4.

Assuming the device to have been constructed and arranged as above described, with the parts in the position in Fig. 3 and with the transmission shaft II and member 22 rotating in a counterclockwise direction, asillustrated bythe arrow in Fig. 3, in order to cause forward movement of the vehicle to which the device is assumed to be attached, such forward movement will be effected independently of the ratchet ring 33, one of the notches 34 of said ring being engaged by the pawl and said pawl in turn being engaged by the latch end 5i of the lever 5t, said lever being forced to the position illustrated in Fig. 3 by the plunger 63 controlled by the spring 54 confined in the recessv 55 between the plunger G3 and the screw plug 63. Such counter-clockwise movement or rotation of the member 22 will tend to force the rollers 31 to the right, as viewed in Fig. 3, or toward the large end of the wedging chambers 35. This movement of the rollers 31 toward the large end of the chambers 35 is assisted by the drag ring 21, the elongated studs 3 riding in the recesses thereof and free rotation of said drag ring being resisted by the springpressed plungers The movement of the rollers 31 to the right, viewing Fig. 3, will cause the studs 33 and 33 to ride in the slots 44, thus positively moving said rollers 31 out of contact with the ratchet ring thus entirely eliminating idling contact of the yrollers 31 with the bore 35 of said ratchet ring during forward movement of the device.

This elimination of idling Contact or engagement on the part of the ,rollers 31 removes the greatest factor of wear therefrom, thus increasing and prolonging the life of the mechanism to a material degree.

Now assume that with the device in the position illustrated in Fig. 3, the machine in which it is incorporated is stopped on an incline. Immediately upon stopping, there would tend to be a retrograde movement ofthe vehicle, turning the shaft l i and member 22 in a clockwise direction as indicated by the arrow in Fig. 4. However, the ratchet ring 33 being held against movement, the drag on the ring 21, together with the clockwise movement of the member 22, will force the rollers 31 toward the small end of their respective chambers and toward the high ends of the slots 44, wedging said rollers between the inner wall of saidchambers and the bore 36 of the ring 33, eifectually preventing any inadvertent reverse movement of the vehicle.

Now assume that it is desired to move the device in a reverse direction, such as by motion under the vehicles own power. rihe gear shift lever its is manipulated to reverse position, which movement will cause a movement of the slide rod l5 and its extension 55 tothe rear, and an engagement of the cam face 5i of said extension with cam face of the lever moving said lever about its pivot 4Q inca counter-clockwise movement, against the tension of the spring-pressed plunger which movement will free the latch 5I from the lever 41. Thereupon, movement of the shaft il and member 22 in a clockwise direction, as indicated by the arrow in Fig. will also tend to move the ring and when this movement occurs, the cam face El of the particular notch 34 in engagement with the pawl 48 will force said pawl out of said notch, to the position illustrated in Fig. e.

will permit reverse movement of the device, as will be readily understood and appreciated. Upon such movement taking place, when the pawl i8 is displaced from its notch 34, the outer end of the arm 59 will drop into the cam grooves 54 and to norma-1 position, and be engaged by the lever as illustrated in Fig. 4, holding the pawl i3 out of engagement with the ring 3,3. Thus, when the gear shift lever I3a. is moved from reverse position to neutral, the device will remain in the position illustratedin Fig.

2; The elongated slot 55 permits movementof the slide rod I5 and its extension 55 to the rear without effecting any vertical movement of the arm 59, as will be appreciated. It should be noted that with the arm lever 5S lifted and held in raised position, the spring 64 will force a notch 5l against the pawl 48 to lock said pawl against the camming action of the surfaces 6l on the ring 33.

Now assume that the device is in neutral, as illustrated'in l, and that it is desired to move to a forward speed. On movement of the gear shift lever I 3a into rst or low gear, the slide rod I5 and its extension 55 will be moved forwardly, and the arm 59 will be engaged by the rearmost wall of the elongated cam groove 56,

f.: raising the arm 5S to the position illustrated in full lines in Fig. 3. This permits the plunger 63 to force the lever 5G in a clockwise rotative movement, the pawl 48 falling to a position against the outer peripheryv of the ring 33. If at this instant, the pawl 68 is in register with one of the notches 311, it will engage said notch and the latch 5I will engage said pawl to hold the same therein. If, however, the pawl 48 is not in register with a notch i, upon the slightest retrograde movement of the vehicle, the ring 33 will be rotated in a clockwise direction, and as soon as the next succeeding notch registers with the pawl f2.8engagement thereof will take place and further retrograde movement be restrained.

Upon movement of the gear shift lever i3d from low or i'lrst gear to either ci the other forward speeds, the arm 59 will be raised out of the cam groove 54, regardless of the direction of movement of the slide rod I4 and its extension 53, tothe position illustrated in dotted lines in Fig. 8, without affecting the relation of the pawl it and ratchet ring 33. Thus the device, in any of the forward speeds, is constantly in operative position, it being necessary to move the gear shift 1 lever i3d to reverse position in order to render the braking device inoperative.

It will be appreciated that when the gear shift lever i3d is being moved from the neutral position, with the device in the position illustrated in Fig. 4, the initiation of movement toward a forward speed will place the device in operative position, without any material time interval being required to effect this result.

In order to eliminate the necessity of `rst moving the gear shift lever into or toward reverse position, and then returning the same to neutral before the vehicle can be moved forwardly or backwardly, as, for example, on the licor of a garage, I provide, on the lever 4l, a lug "IG in register with a lug 'II on the lever Sil. Thus, when the rod I is moved rearwardly, as will be the case'when 'the gear shift lever I3 is moved toward reverse position, the cam face 6I of its extension 55, engaging the cam face 52 on the lever 5d, will swing said lever 5B about its pivot 49, bringing the lug 'II into engagement with the lug IB and rocking the lever 4l' about its pivot 4t until the latch 48 is raised from its cooperating notch 3K3 in the ratchet ring 33. This movement, of course, will be against the pressure of the spring pressed plunger 63, and as the lever 5!) is rocked in a counter-clockwise direction, the arm 59 will drop to its normal position, as clearly illustrated in Fig. 4.

Thereupon, whether the gear shift rod I5 is retained in the; position illustrated in `lig. 4, or whether it is returned to neutral position, the latch 68 will be held out of engagement with the ratchet ring 3.3 by means of the lever 55.! bearing against the outer side of the extension 55. It will thus be Iappreciated that the lugs j'IG and li afford means to positively disengage the locking elements` comprising the latch 48 and the notches 3d, `rather than relying upc-n the camming actions of the cam 4faces Sl on reverse rotation ci the ring 33, a feature that will be instantly rd'fllllarellt to and understood by those .skilledin this art.

This feature also eliminates diiiiculties which might possibly ari-,se when relying upon the cam ming action to disengage the latch 48. For example, if the gears should not be exactly in register, it would frequently be difficult to effect rearward movement of the vehicle in order to exert such camming action. The novel feature just above described, however, entirely obviates and eliminates this difhculty. l

Furthermore, under some circumstances, such, for` example, as when a vehicle is rolling rear wardly, and the operator moves the gear shift lever IBa to one of the forward speeds during such rearward movement, damage, injury, and considerable shock are likely to be caused by the instantaneous meshing or engagement of the latch 48 with one of the notches 34.' as the ring 33Y is rotating in its reverse direction. This is obviated however, by mounting the ratchetring 33 on a solid `member attached to the casing, as aforesaid.

As above explained, the said latch 48 will re-` main in the notch engaged thereby until the gear shift lever i3d is again moved toward reverse position.

It will thus be appreciated that I have devised a simple, positive, serviceable, and eicient, automatically operable reverse brake mechanism, and

Vsince I believe that the same is novel, I have therefore claimed said device broadly in this application.

While I have necessarily described my present invention some-what` in detail, it will-be appreciated that I may vary the size, shape and arrangement of parts within reasonably wide limits without departing from the spirit of the invention.

My invention is further described and defined in the form of` claims as follows:

l. In a device of the kind described, the Vcombination of a driven member, means for applying power thereto to rotate the same in either direction, a locking element carried by said driven member, a ratchet ring surrounding said driven member and cooperating with said locking ele-` ment to prevent rotation of the driven member in a reverse direction, means including a drag ring in constant engagement with said locking ele-ment to hold said'locking element out of engagement with the ratchet ring on rotation of the driven member in a forward direction, and spring controlled means to normally prevent rotative move-ment of said ratchet ring.

2. In a device of the kind described, the combination with a transmission gearing, including a transmission shaft, of a driven member carried by said shaft, a locking element carried by P said driven member, a ratchet ring surrounding said driven member and cooperating with said locking element to prevent rotation of the driven member in a reverse direction, means including a resiliently controlled drag ring in constant engagement with said locking element to hold said locking element out of engagement with the ratchet ring on rotation of the driven member in a forward direction, a pawl normally engaging said ratchet ring to prevent rotativeV movement of said ratchet ring, and spring controlled means to hold said pawl in lockingposition.`

3. In a device of the kind described, the combination of a driven member, means for applying power thereto to rotate the same in ,either direction, said driven member having a wedgeshaped recess therein, a member fixed to said driven member at each side thereof and having inclined guiding slots therein adjacent to said recess, a locking roller located in said recess, studs on said roller riding in said slots, a ratchet ring surrounding said driven member and cooperating with said locking roller to prevent rotation of the driven member in a reverse direction, and a resiliently controlled drag ring to hold said locking roller out of engagement with the ratchet ring on rotation ofthe driven member in a forward direction.

4. In a device of the kind described, the combination of a driven member, means for applying power thereto to rotate the same in either direction, said driven member having a wedge-shaped recess therein, a member fixed to said driven member at each side thereof and having inclined arcuate guiding slots therein adjacent to said recess, a locking roller located in said recess, studs on said roller riding in said slots, a ratchet ring surrounding said driven member and cooperating with said locking roller to prevent rotation of the driven member in a reverse direction, and a resiliently controlled drag ring to hold said locking roller out of engagement with the ratchet ring on rotation of the driven member in :a forward direction,

5. In a device of the kind described, the combination of a driven member, means for applying power thereto to rotate the same in either directherein engaged by one of the studs on said roller to hold said locking roller out of engagement with said ratchet ring Ion rotation of the driven member in a forward direction.

6. In a device of the kind described, the combination of a driven member, means for applying Ypower thereto to rotate the saine in either direction, said driven member having a wedge-shaped recess therein, a member fixed to said driven member at each side thereof and having inclined guiding slots therein adjacent to said recess, a locking roller located in said recess, studs on said rollers riding in'said slo'ts, a ratchet ring surrounding said driven member and cooperating with said locking roller to prevent rotation of the driven member in a reverse direction, and a resiliently controlled drag ring having a radial slot therein engaged by one of the studs on said roller to hold said locking roller out of engagement with said ratchet ring on rotation of the driven member in a forward direction, said drag ring being spaced from said driven member and free from the direct rotating influence thereof.

'7, In a device of the kind described, the combination of a driven member, means for applying power thereto to rotate the same in either direction, said driven member having a wedge-shaped recess therein, a member fixed to said driven member at each side thereof and having inclined guiding slots therein adjacent to said recess, a locking roller located in said recess, studs on said rollers riding in said slots, a xed abutment adjacent to said driven member, a ratchet ring rotat-ably mounted on said abutment and projecting over and surrounding said driven member and c0- operating with said locking roller to prevent rotation of the driven member in a reverse direction, and a resiliently controlled drag ring having a radial slot therein engaged by one of the studs on said roller to Vhold said locking roller out of engagement with said ratchet ring on rotation of the driven member in a forward direction, said drag ring being spaced fromv said driven member and free from the direct rotating inuence thereof.

8. In a device of the kind described, the combination of a driven member, means for applying power thereto to rotate the same in either direction, said driven member having a wedge-shaped recess therein, a member fixed to said driven member at each side thereof and having inclined guiding slots therein adjacent to said recess, a locking roller located in said recess, studs on said roller riding in said slots, a iXed abutment adjacent to said driven member, a ratchet ring rotatably mounted on said abutment and projecting over and surrounding said driven member but spaced therefrom and cooperating with said locking roller to prevent rotation of the driven member in a reverse direction', and a resiliently controlled drag ring having a radial slot therein engaged by one of the studs on said roller to hold said locking roller out of engagement with said ratchet ring on rotation of the driven member in a forward direction, said drag ring being spaced from said driven member and free from the direct rotating influence thereof.

9. In a device Iof the kind described, the combination of a driven member; means for applying power thereto to rotate the same in either direction, said driven member having a wedge-shaped recess therein, a locking roller located in said recess, a ratchet ring surrounding said driven member and cooperating with said locking roller to prevent rotation of the driven member in a reverse direction, said ratchet ring being of greater width than said driven member and mounted independently thereof, and a resiliently controlled drag ring to hold said locking roller out of engagement with the ratchet ring on rotation of the driven member in a forward direction.

CARL A. MATSON. 

